Watchcase



F. MARTI v wATcHcAsE Jan. 12, 1943.

Filed Dec. 14, 1938 2 Sheets-Sheet l F. MARTI WATCHCASE Jan. 12, 1943.

Filed Deo. 14, 1938 2 sheets-sheet 2 anni?? i Patented Jan. 12, 1943UNITED STATES PATENT OFFICE WATCHCASE Fritz Marti, La Chaux de Fonds,Switzerland Application December 14, 1938, Serial No. 245,763 InSwitzerland December 29, 1937 rlhis invention relates to watch cases andmore particularly to the type of tight watch cases provided withunbreakable crystals and to a method for their manufacture.

The object of the invention is the provision of a watch case of theabove type in which the unbreakable crystal is inseparably united underheat and pressure by an adhesive engagement to the portion of the case,which is destined to carry the crystal.

In method of manufacturing said watch case the crystal and the crystalcarrying portion of the case, are both preliminarily heated, placeddirectly into Contact with each other and pressed one against the other.This pressure is maintained until these two parts are cooled down.

The invention consists in the construction and arrangement and in themethod for manufacture of certain parts of the watch case so that awatertight joint is effected, as will be apparent from the followingdescription and claims, reference being had to the accompanying drawingswhich show several forms of embodiment of the present invention.

In the drawings,

Figure l is an axial section or a first embodiment.

Figure 2 illustrates the method for manufacture of this embodiment.

Figure 3 shows an axial section of a second embodiment.

Figures 4 to 9 inclusive are cross sections of modifications of details.

' Figure l0 is a plan View of a third embodiment of oblong shape.

Figure 11 is a semi section along line ll-ll of Fig. l0.

Figure 12 is a section along line l2--l2 of Fig. 10.

The embodiment represented in Fig. 1 comprises two elementary casesdisposed one in the other; the external casing being constituted by abottom I and a crystal frame 2, both of metal; the latter of saidmembers being adapted to bear externally upon a crystal the internalcasing comprising a bottom 3, a movement ring 4 and the said crystal 5.This crystal is inseparately united under heat and pressure by adhesionto the movement ring 4, which dispenses with interposition of anothersubstance, such as paste for instance. The movement ring 4 of metalpresents a circular projection fl which in radial cross section isbroader at its end than at its base. This projection is engaged in acorresponding circular groove in the crystal in such a manner that thecrystal i core 9.

and the movement ring cannot be separated but by destroying or meltingthe crystal. The latter presents on its border a shoulder 'l appliedagainst the internal face of the border of the movement ring forabsorbing the pressure which could be exerted on the crystal with aringer, for instance.

This case can be manufactured in the following manner:

The preliminarily heated movement ring 4 is placed in a mould formed ofa wall 8 and of a A leaf of unbreakable crystal Ill preliminarily heatedto a sufficiently high temperature so that it will be soft is thendisposed on the upper surface of the core. Afterwards the piston II islowered into the position shown in dash lines in Fig. 2, exerting apressure on the soit leaf and thereby inseparably uniting by adhesionthe crystal to the movement ring. This pressure is maintained until thetwo parts are cooled down. Instead of the piston l i, a cylinder l2could be used by applying it against the leaf as in the position shownin dash lines in Fig. 2', and by introducing compressed air into thecylinder whereby the soft leaf of crystal would be applied against themovement ring.

The watch case shown in Fig. 3 is a single casing. The crystal I3 isxedto the frame or case member I4 as above described, which meansadhesively by heat and pressure. The crystal presents two circularprojections l5 penetrating into the corresponding grooves of the frameor case member.

The Figures 4 to 9 inclusive are cross sections of modifications ofthese projections and grooves.

The third embodiment of the watch case represented in Figs. 10 to l2 isformed of an exterior casing constituted by a movement frame IS ofmetal, and of an interior casing or case member. The latter comprises ametal ring l1 and an unbreakable crystal I8, the crystal i8 being fixedto the ring l1 over the entire width thereof by adhesion under heat andpressure and also by the mutual engagement of a peripheral projection onsaid ring and a corresponding groove in the crystal, thus effecting asolid and watertight joint between the two parts. The interior casingcomprises moreover a metal bottom I9 presenting on its exterior face alongitudinal rectangular recess 2U wherein the median portion of aspring leaf 2| is placed. The two ends 22 and 23 of this spring are eachbent at a right angle and are terminated by claws 24 engaged in grooves25 of the movement frame IB.

The bottom I9 presents along the periphery of its internal face aprojection 26, and between the interior rims of the ring Il and of thecrystal I8 is a groove provided wherein a joint 2'I of elastic material,pleXigum for instance, is disposed.

In the position shown in the drawing the projection 26 is applied bymeans of the spring 2| against the joint ring 2'I, as at the same timethe whole interior casing under the action of this spring is pressedagainst the top border of the movement frame I6, whereby an excellenttightness is obtained. .Furthermore the crystal I8 being xed to the ringIl over the entire width thereof, the two pieces constitute a very solidand watertight aggregate. v

For the winding shaft a tube 2S is provided traversing two coaxial holesin the crystal vI 8 and the ring I'I, the hole in the latter presentinga thread 29, whereinto the tube 28, threaded latzits interior portion isscrewed. A shoulder Si) provided on the tube presses then against thecrystal so that a tight joint is obtained in this spot.

While the represented examples show some preferred forms of theinvention, it is understood that other constructions and vcombinationsof parts may be made which fall within the scope of the appended claims.

I claim:

l. In a tight watch case comprising an unbreakage crystal, a crystalcarrying ring, said crystal being inseparably united under heat andpressure by adhesion to the ring over the entire width thereof forpresenting a tight junction'between said crystal and said ring, saidcrystal and said ring being provided with coinciding adjacent apertures,the aperture in the crystal being smooth and the aperture in the ringbeing threaded, a tube for the winding shaft, traversing said apertures,a circular shoulder round the exterior side of said tube, said tubebeing screwed into the threaded ring portion, so as to press theshoulder against the crystal.

2. In a tight watch case comprising an unbreakage crystal, a crystalcarrying ring, said crystal being inseparably united under heat andpressure `by adhesion to the ring over the entire width thereof forpresenting a tight junction between said crystal and said ring, a groovebetween the bottom rims of saidring and said crystal, and a joint ringof elastic material disposed therein.

3. In a tight watch case, in combination a case member and an unbreakagecrystal member, each having adjoining contact surfaces, andbeinginseparably united under heat and pressure Vby an adhesiveengagement of their adjoining contact surfaces so as to form awatertight joint therebetween.

4. In a tight watch case, in combination a case member, an unbreakablecrystal member, one of said members formed with at least one peripheralgroove, the other of said members having at least one peripheralprojection conforming to and litvting into said groove, said case memberand crystal member having adjoining contact surfaces and beinginseparably united under heat and pressure by adhesion of theiradjoining Contact surfaces and in particular by the mutual engagement ofsaid groove with said projection so as to form a watertight jointbetween the case member and the crystal member.

5. In a tight watch case, in combination a case band having at its upperend a peripheral groove,

` and an unbreakable crystals formed with a downstanding flange adaptedto contact with said case band over the entire width thereof andpresenting aV peripheral projection conforming to and rltting into saidgroove, said member and crystal being inseparably united by the adhesionof their adjoining contact surfaces and in particular by the mutualadhesive engagement of said projection with said groove so as to form asingle watertight body.

6. A watch case of the character described comprising a casing, agrocved crystal carrying ring within said casing, an unbreakable crystalprovided with a peripheral projection for engagement with the groove insaid ring between said casing and said ring and adhesively contactingthe adjacent side wall of the ring over the outer side surface thereof,a plate member underneath said ring formed with a longitudinal recessand an upstanding peripheral ilange, a packing member between the lowerperipheral abutting edges of said ring and said crystal upon which thesaid peripheral flange bears, and a spring leaf in the longitudinalrecess of said plate extending exteriorly of the casing and removablyengaged therewith to releasably hold the parts together.

'7. A tight watch case including a case member and a bottom and sidewalls and shaped to receive the inner workings of a watch, anunbreakable crystal member adjacent said oase member, each of saidmembers having adjoining contact surfacesY one of said members having atleast one peripheral groove, the other of said members having at leastone peripheral projection oonforming to and itting into said groove,both of said members being inseparably united by heat and pressure attheir 'adjoining contact surfaces and in particular by the mutualadhesion engagement of said groove with said projection so as to form awatertight joint between said case member and said unbreakablecrystalmember.

8. A watch case as claimed in claim 7, in which the opposed side wallsof the peripheral groove are not parallel to each other.

FRITZ MARTI,

